1952 Federal bill for Upper Basin projects generates national opposition because one project, Echo Dam, would flood Dinosaur National Monument. Dam was removed from subsequent legislation signed in 1956.

1964 U.S. Supreme Court Decree Arizona v. California holds California to 4.4 million, Arizona to 2.8 million and Nevada to 300,000 acre-feet annually in normal years as provided in the Boulder Canyon Project Act.

1968 CAP is included in Colorado River Basin Project Act. Proposed Grand Canyon dam removed after one of biggest environmental battles in U.S. history.

1973 Mexico and U.S. approve Minute 242 of the 1944 Water Treaty, establishing salinity standards for water delivered to Mexico.

Mexico and U.S. subsequently sign Minute 318, an interim agreement that allows Mexico to store part of its allocation in Lake Mead while repairs are made to infrastructure damaged during the April 2010 earthquake.

Sacramento Superior Court validates QSA and 11 related agreements. The County of Imperial and Imperial County Air Pollution Control District filed an appeal.

2014 A pulse flow is released into the Colorado River Limitrophe (the 24-mile stretch that forms the U.S.-Mexico border) and Delta. Water flows to areas being restored by conservation groups and sets the stage for future management of what was once more than 2 million acres of riparian habitat and wetlands vital to birds and wildlife.

City of Phoenix creates the Colorado River Water Resiliency Fund, in which about $5 million annually pays for things such as well sharing and storing the city’s unused Colorado River water in underground recharge facilities.

2015 The Moving Forward Phase 1 Report is released. It includes the recommendations from three workgroups focused on water use efficiency (urban and agricultural) and environmental and recreational flows.

2016 - Major water suppliers in the Lower Basin begin begin work on a Drought Contingency Proposal that would ensure Arizona, California and Nevada are enrolled in what they agree is a shortage-sharing platform to avoid the undesirable aspects of Lake Mead falling to 1,025 feet above sea level – the lowest shortage trigger level contemplated in the 2007 Guidelines.

2017 – Heavy winter snows in the Rocky Mountains provide enough water to the Colorado River to avoid any possibility of a shortage declaration in 2018, according to the Bureau of Reclamation.

2017 - United States and Mexican governments sign an agreement to the 1944 Water Treaty between the two countries called Minute 323. The Minute extends 2012’s Minute 319 that gave Mexico greater flexibility in managing its Colorado River allotment. The latest agreement provides mechanisms for increased conservation and water storage in Lake Mead to help offset the effects of drought and prevent a shortage from being triggered. Minute 323 dedicates 210,000 acre-feet of water over nine years for environmental restoration work in the Colorado River Delta